1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to providing contents stored in a server to clients, and more particularly, to providing contents in such a manner as to protect content consumers' privacy.
2. Description of the Related Art
The widespread development of broadband networks and affordable computing devices promotes the penetration of digital contents into every aspect of daily life. The demand for these digital multimedia contents, such as television (TV) programs, films, and music, increases tremendously with improvements in quality and access.
Unlike traditional analog contents which suffer from quality degradation when copied, digital contents can be perfectly duplicated and then easily disseminated. Accordingly, piracy, which is the use of contents without a content provider's permission, often takes place. In order to prevent such piracy, much research has been done on digital rights management (DRM).
In general, a content server provides contents to clients based on DRM. That is, if a client attempting to use a specific item of content passes authentication, the content server, which encrypts and manages contents, provides the corresponding encrypted content to the authorized client along with a decryption key. The authentication may be performed by the content server or by a separate authentication server.
In the DRM field, efforts so far have been concentrated on prevention of access by unauthorized users, and traditional content distribution approaches have not seriously considered consumer privacy issues. That is, all consumption records are exposed to a content provider when a consumer provides his or her authentication information to the content provider. Accordingly, the content provider can determine what content has been used by the consumer, thereby failing to protect the consumer's privacy.
Also, when content encrypted with a predetermined encryption key is sold to a plurality of consumers, and one of the consumers distributes a decryption key without a content provider's permission, the perpetrator cannot be traced.